Due to the characteristic of fine grain size, complex mineral composition, low iron content and so on, the iron ore resources, such as fine hematite, oolitic hematite, endoscopy limonite and stacked iron tailings, are difficult to obtain ideal technical and economic indicators by conventional mineral processing technology, and difficult to obtain large-scale industrial development and utilization, or some resources may be developed but the utilization efficiency is very low.
Magnetizing roasting-magnetic separation technology is an effective way to deal with the above mentioned iron ore resources. The suspension magnetizing roasting has the advantages of sufficient gas-solid contact, good heat and mass transfer effect, and fast reaction speed. At present, it is widely used in the treatment of refractory iron ore. For example, the invention of “suspension magnetizing roasting furnace” with SIPO publication number of CN200720014578, and the invention of “iron mineral suspension magnetizing roasting system and roasting technology” with CN200710012802.
However, the abovementioned invention can only get a single roasting product, and the roasting product should be cooled down to the room temperature to get the products of different roasting qualities, and the single roasting product is prone to over-firing or under-burning during the roasting process.